The operation to retake the Iraqi city of Mosul from so-called Islamic State militants is progressing faster than planned, the Iraqi prime minister says, according to BBC News.

Haider al-Abadi said the move showed "rapprochement" and unity of purpose between Iraqi and Kurdish forces. His comments came as Kurdish fighters launched a large-scale operation east and north of Mosul.

The Iraqi army has been moving from the south, and special forces have now joined the offensive.

Mosul has been in the hands of IS since 2014 and is the militants' last major Iraqi stronghold.

The offensive to retake it began on Monday. Up to 1.5 million civilians are thought to still be inside the city. Those inside report that they are running out of basic supplies.

There are reports that some IS leaders have fled, but there are thought to be up to 5,000 IS fighters still in the city.

The Iraqi prime minister made his comments via video-link to an international meeting in Paris on the future of Mosul.

"The forces are pushing towards the town more quickly than we thought and more quickly than we had programmed in our campaign plan," he said.

He hailed co-operation between the army and Kurdish troops, saying they were "fighting harmoniously together" to free Iraqi territory from IS.

French President Francois Hollande, hosting the meeting, warned that IS fighters were fleeing to Raqqa, the militant group's stronghold in Syria, and said efforts must be made to stop them.

The whereabouts of IS leader Abu Bakr al-Baghdadi are unknown. Some reports say he is in Mosul, but others say he has fled the northern Iraqi city.